The general configuration of an apparatus for operating a variable siphon tube of a toilet is shown in FIGS. 1 and 2. As shown in these figures, the apparatus for operating the variable siphon tube apparatus comprises a variable siphon tube 10 of which both ends are connected to a bowl 1 and a soil pipe 2 via a flexible tube 3, respectively; an upper bellows tube 20 that communicates with a water supply passage 1a of the bowl 1 and also communicates with the variable siphon tube 10 via an auxiliary tube 4; a guide bar 30 of which a lower end is fixed onto an installation bottom surface B and an upper end is installed to penetrate through a bottom plate 21 of the upper bellows tube 20; a transverse bar (not shown) which is connected to a middle point of the guide bar and connected to the bottom plate 21 by means of a connection bar; a roller 40 which is installed to be freely rotatable outside of the transverse bar and seated on a bend 11 of the variable siphon tube 10; and a return spring 50 which is installed below the transverse bar to perform a function of restoring the transverse bar to its original state.
However, a toilet with such a conventional variable siphon tube has the following problems.
First, a return spring may be tangled when it is operated.
That is, while the return spring is compressed, spring coils are tangled with one another and thus the spring is not smoothly restored. Therefore, an operating error occurs in that the variable siphon tube 10 may not be restored to its original state even after water in the upper bellows tube 20 is fully discharged.
Second, due to friction between the return spring 50 and the guide bar 30, the operating reliability of the toilet is reduced and noise is produced from the toilet.
That is, while the friction occurs between the return spring and the guide bar 30 passing through the center of the return spring, friction noise and wear on the guide bar are produced. Further, the compressing and restoring operation of the return spring is not smooth. Therefore, there is a problem in that the raising operation of the variable siphon tube 10 is not constant and regular.
Third, it is difficult to install the guide bar 30 on the installation bottom surface B. That is, since the bottom surface is constructed from brittle tiles, there is another problem in that the tiles are easily broken when the guide bar is installed on the tiles. Therefore, there is a difficulty in installing the guide bar on the tiles.
Fourth, since the auxiliary tube 4 is positioned above a highest water level of the variable siphon tube 10, an offensive odor generated from a toilet waste storage tank T is discharged to the outside of the toilet through the variable siphon tube, the auxiliary tube, the upper bellows tube, the water supply passage and the bowl. Therefore, it is difficult to isolate the discharged odor.
Further, since an inlet end of the auxiliary tube 4 is positioned on the flank of the upper bellows tube 20, the remaining water that was not discharged through the auxiliary tube may remain in the bottom floor of the upper bellows tube when the upper bellows tube 20 was restored. Therefore, there is a problem in that the amount of water stored in the bowl 1 is decreased in proportion to the amount of water remaining in the upper bellows tube.
Fifth, when the rear portion of the bowl 1 is brought into close contact with an installation wall surface W as shown in FIG. 2, it should have a sufficient length such that the bend 11 of the variable siphon tube 10 does not interfere with the installation wall surface W during its circular motion. Consequently, since the length of the bowl in a fore-and-aft direction should be further lengthened by a length Δl, it is difficult to make the toilet slim.
Sixth, there is strong likelihood that the toilet wastes may adhere to the bellows tubes 3 connected to the inlet and outlet of the variable siphon tube 10.
That is, since the bellows tube 3 is formed with several folds on an inner surface thereof, the wastes may adhere and stick to the folds of the bellows tube during their discharge. Therefore, the smooth operation of the bellows tubes is hindered, and thus, the expansion and contraction of the bellows tube are adversely influenced.